Merge pull request #18 from pcwalton/master

Several improvements
Added swap_buffers through SDL_GL_SwapBuffers
Merge pull request #21 from FrozenCow/swapbuffers

Added swap_buffers through SDL_GL_SwapBuffers
Unsafe functions now instead use internal Unsafe blocks, to match
changes in syntax
Wrap calls to low-level functions in unsafe { ... } blocks for language changes
Merge pull request #22 from pcwalton/unsafe

Wrap calls to low-level functions in unsafe { ... } blocks for language changes
Corrected tests to no longer use nonexistent str::is_not_empty
Added basic support for mouse-events
Merge pull request #23 from FrozenCow/mousevents

Added basic support for mouse-events
Fixed compilation error on 32bit systems
Merge pull request #24 from FrozenCow/32bitfix

Fixed compilation error on 32bit systems
Migrated to Incoming's new Fail syntax
Turns out SDL_UnlockSurface was supposed to be returning void rather
than int. This caused the with_lock method of Surface to sometimes
inexplicably fail, as the underlying library was returning junk to Rust.
Changed it to Void and all appears happy.
Added unit test for with_lock
Add pkg.rs for rustpkg support and change fail! to die!
Replaced oldschool type for struct
Merge pull request #26 from z0w0/master

Add rustpkg support
Surfaces now track whether they're supposed ot be freed. Fixes #27
Switched fail! out for the more correct die!
Implement `img::load_img` (`IMG_Load` from `SDL_image`).

Because life without transparent images is so boring...